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Niels Bjerrum
Niels Janniksen Bjerrum (11 March 1879 in Copenhagen – 30 September 1958) was a Danish chemist. Niels Bjerrum was the son of ophthalmologist Jannik Petersen Bjerrum, and started to study at University of Copenhagen in 1897. He received his Master's degree in 1902 and his Doctor's degree in 1908, and did research in coordination complex chemistry under Sophus Mads Jørgensen. He became a docent in 1912, and in 1914 he became professor of chemistry at the Royal Agricultural College (''Landbohøjskolen'') in Copenhagen, as successor of Odin Tidemand Christensen. He stayed on this post until his retirement in 1949, and from 1939 to 1946 he was also the Director of the College. Importantly, Bjerrum introduced the concept of three forms of molecular energy, translational, vibrational and rotational which was important in understanding vibrational spectroscopy. He is also noted for the theory behind the Bjerrum length, and the Bjerrum plot. Bjerrum also performed some of the f ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copenhagen
Copenhagen ( or .; da, København ) is the capital and most populous city of Denmark, with a proper population of around 815.000 in the last quarter of 2022; and some 1.370,000 in the urban area; and the wider Copenhagen metropolitan area has 2,057,142 people. Copenhagen is on the islands of Zealand and Amager, separated from Malmö, Sweden, by the Øresund strait. The Øresund Bridge connects the two cities by rail and road. Originally a Viking fishing village established in the 10th century in the vicinity of what is now Gammel Strand, Copenhagen became the capital of Denmark in the early 15th century. Beginning in the 17th century, it consolidated its position as a regional centre of power with its institutions, defences, and armed forces. During the Renaissance the city served as the de facto capital of the Kalmar Union, being the seat of monarchy, governing the majority of the present day Nordic region in a personal union with Sweden and Norway ruled by th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Albert Einstein
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theory of relativity, but he also made important contributions to the development of the theory of quantum mechanics. Relativity and quantum mechanics are the two pillars of modern physics. His mass–energy equivalence formula , which arises from relativity theory, has been dubbed "the world's most famous equation". His work is also known for its influence on the philosophy of science. He received the 1921 Nobel Prize in Physics "for his services to theoretical physics, and especially for his discovery of the law of the photoelectric effect", a pivotal step in the development of quantum theory. His intellectual achievements and originality resulted in "Einstein" becoming synonymous with "genius". In 1905, a year sometimes described as his ' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Danish Physical Chemists
Danish may refer to: * Something of, from, or related to the country of Denmark People * A national or citizen of Denmark, also called a "Dane," see Demographics of Denmark * Culture of Denmark * Danish people or Danes, people with a Danish ancestral or ethnic identity * A member of the Danes, a Germanic tribe * Danish (name), a male given name and surname Language * Danish language, a North Germanic language used mostly in Denmark and Northern Germany * Danish tongue or Old Norse, the parent language of all North Germanic languages Food * Danish cuisine * Danish pastry, often simply called a "Danish" See also * Dane (other) * * Gdańsk * List of Danes * Languages of Denmark The Kingdom of Denmark has only one official language, Danish, the national language of the Danish people, but there are several minority languages spoken, namely Faroese, German, and Greenlandic. A large majority (about 86%) of Danes also s ... {{disambiguation Language and natio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1958 Deaths
Events January * January 1 – The European Economic Community (EEC) comes into being. * January 3 – The West Indies Federation is formed. * January 4 ** Edmund Hillary's Commonwealth Trans-Antarctic Expedition completes the third overland journey to the South Pole, the first to use powered vehicles. ** Sputnik 1 (launched on October 4, 1957) falls to Earth from its orbit, and burns up. * January 13 – Battle of Edchera: The Moroccan Army of Liberation ambushes a Spanish patrol. * January 27 – A Soviet-American executive agreement on cultural, educational and scientific exchanges, also known as the "Lacy-Zarubin Agreement, Lacy–Zarubin Agreement", is signed in Washington, D.C. * January 31 – The first successful American satellite, Explorer 1, is launched into orbit. February * February 1 – Egypt and Syria unite, to form the United Arab Republic. * February 6 – Seven Manchester United F.C., Manchester United footballers are among the 21 people killed i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
1879 Births
Events January–March * January 1 – The Specie Resumption Act takes effect. The United States Note is valued the same as gold, for the first time since the American Civil War. * January 11 – The Anglo-Zulu War begins. * January 22 – Anglo-Zulu War – Battle of Isandlwana: A force of 1,200 British soldiers is wiped out by over 20,000 Zulu warriors. * January 23 – Anglo-Zulu War – Battle of Rorke's Drift: Following the previous day's defeat, a smaller British force of 140 successfully repels an attack by 4,000 Zulus. * February 3 – Mosley Street in Newcastle upon Tyne (England) becomes the world's first public highway to be lit by the electric incandescent light bulb invented by Joseph Swan. * February 8 – At a meeting of the Royal Canadian Institute, engineer and inventor Sandford Fleming first proposes the global adoption of standard time. * March 3 – United States Geological Survey is founded. * March 11 – ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ideal Solution
In chemistry, an ideal solution or ideal mixture is a solution that exhibits thermodynamic properties analogous to those of a mixture of ideal gases. The enthalpy of mixing is zero as is the volume change on mixing by definition; the closer to zero the enthalpy of mixing is, the more "ideal" the behavior of the solution becomes. The vapor pressures of the solvent and solute obey Raoult's law and Henry's law, respectively, and the activity coefficient (which measures deviation from ideality) is equal to one for each component. The concept of an ideal solution is fundamental to chemical thermodynamics and its applications, such as the explanation of colligative properties. Physical origin Ideality of solutions is analogous to ideality for gases, with the important difference that intermolecular interactions in liquids are strong and cannot simply be neglected as they can for ideal gases. Instead we assume that the mean strength of the interactions are the same between all t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Osmotic Coefficient
An osmotic coefficient \phi is a quantity which characterises the deviation of a solvent from ideal behaviour, referenced to Raoult's law. It can be also applied to solutes. Its definition depends on the ways of expressing chemical composition of mixtures. The osmotic coefficient based on molality ''m'' is defined by: \phi = \frac and on a mole fraction basis by: \phi = -\frac where \mu_A^* is the chemical potential of the pure solvent and \mu_A is the chemical potential of the solvent in a solution, ''M''A is its molar mass, ''x''A its mole fraction, ''R'' the gas constant and ''T'' the temperature in Kelvin. The latter osmotic coefficient is sometimes called the rational osmotic coefficient. The values for the two definitions are different, but since \ln x_A = - \ln \left(1 + M_A \sum_i m_i \right) \approx - M_A \sum_i m_i, the two definitions are similar, and in fact both approach 1 as the concentration goes to zero. Applications For liquid solutions, the osmotic coeffi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transactions Of The Faraday Society
The ''Journal of the Chemical Society, Faraday Transactions'' was a peer-reviewed scientific journal published from 1905 until 1998. The journal was originally published by the Faraday Society under the name ''Transactions of the Faraday Society'' and was renamed in 1972. History The journal began its publication in 1905 as ''Transactions of the Faraday Society''. When the society merged with the other chemistry societies of the United Kingdom to form the Royal Society of Chemistry, the publication of the journal was transferred to the Chemical Society in 1972 as part of the merger negotiations. The journal was renamed ''Journal of the Chemical Society, Faraday Transactions'', and split in two (''Faraday Transactions I: Physical Chemistry in Condensed Phases'' and ''Faraday Transactions II: Molecular and Chemical Physics''). After the merger, the Royal Society carried the publication until its end. In 1990, the two journals merged into a single ''Journal of the Chemical Society, Far ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ion Association
In chemistry, ion association is a chemical reaction whereby ions of opposite electric charge come together in solution to form a distinct chemical entity. Ion associates are classified, according to the number of ions that associate with each other, as ion pairs, ion triplets, etc. Ion pairs are also classified according to the nature of the interaction as contact, solvent-shared or solvent-separated. The most important factor to determine the extent of ion association is the dielectric constant of the solvent. Ion associates have been characterized by means of vibrational spectroscopy, as introduced by Niels Bjerrum, and dielectric-loss spectroscopy. Classification of ion pairs ''Ion pairs'' are formed when a cation and anion, which are present in a solution of an ionizable substance, come together to form a discrete chemical species. There are three distinct types of ''ion pairs'', depending on the extent of solvation of the two ions. For example, magnesium sulphate ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bohr Model
In atomic physics, the Bohr model or Rutherford–Bohr model, presented by Niels Bohr and Ernest Rutherford in 1913, is a system consisting of a small, dense nucleus surrounded by orbiting electrons—similar to the structure of the Solar System, but with attraction provided by electrostatic forces in place of gravity. It came after the solar system Joseph Larmor model (1897), the solar system Jean Perrin model (1901), the cubical model (1902), the Hantaro Nagaoka Saturnian model (1904), the plum pudding model (1904), the quantum Arthur Haas model (1910), the Rutherford model (1911), and the nuclear quantum John William Nicholson model (1912). The improvement over the 1911 Rutherford model mainly concerned the new quantum physical interpretation introduced by Haas and Nicholson, but forsaking any attempt to align with classical physics radiation. The model's key success lay in explaining the Rydberg formula for the spectral emission lines of atomic hydrogen. While the Ry ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Niels Bohr
Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922. Bohr was also a philosopher and a promoter of scientific research. Bohr developed the Bohr model of the atom, in which he proposed that energy levels of electrons are discrete and that the electrons revolve in stable orbits around the atomic nucleus but can jump from one energy level (or orbit) to another. Although the Bohr model has been supplanted by other models, its underlying principles remain valid. He conceived the principle of complementarity: that items could be separately analysed in terms of contradictory properties, like behaving as a wave or a stream of particles. The notion of complementarity dominated Bohr's thinking in both science and philosophy. Bohr founded the Institute of Theoretical Physics at the University of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Walther Nernst
Walther Hermann Nernst (; 25 June 1864 – 18 November 1941) was a German chemist known for his work in thermodynamics, physical chemistry, electrochemistry, and solid state physics. His formulation of the Nernst heat theorem helped pave the way for the third law of thermodynamics, for which he won the 1920 Nobel Prize in Chemistry. He is also known for developing the Nernst equation in 1887. Life and career Early years Nernst was born in Briesen in West Prussia (now Wąbrzeźno, Poland) to Gustav Nernst (1827–1888) and Ottilie Nerger (1833–1876). His father was a country judge. Nernst had three older sisters and one younger brother. His third sister died of cholera. Nernst went to elementary school at Graudenz. He studied physics and mathematics at the universities of Zürich, Berlin, Graz and Würzburg, where he received his doctorate 1887. In 1889, he finished his habilitation at University of Leipzig. Personal attributes It was said that Nernst was mechanically min ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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